1. Field of the Invention
The present invention relates to a lock, especially to a tubular lock with enhanced safety.
2. Description of the Prior Arts
Lock is a common device to protect property from being stolen, and also a device that needs a key to unlock.
Lock has several different types. Tubular lock is one of the common locks. With reference to FIG. 7, a conventional tubular lock comprises a casing 91, a driving pin seat 92, a key pin seat 93 and multiple positioning assemblies 94. The driving pin seat 92 is mounted rotatably in the casing 91 and has multiple driving pinholes 921. The key pin seat 93 is mounted securely in the casing 91 and has multiple key pin recesses 931. Each positioning assembly 94 is mounted through a corresponding driving pinhole 921 and is mounted in a corresponding key pin recess 931. Each positioning assembly 94 comprises a driving pin 941, a key pin 942 and a resilient element 943. The driving pin 941, the key pin 942 and the resilient element 943 abut against each other in sequence. The driving pin 941 is mounted through the corresponding driving pinhole 921. The key pin 942 is mounted through the corresponding driving pinhole 921 and is mounted in the corresponding key pin recess 931. The resilient element 943 is mounted in the corresponding key pin recess 931.
When the tubular key is used, the key is inserted in the casing 91. The key has multiple recesses with different depths. Those recesses push and move the positioning assemblies 94. When the correct key is inserted, each interface between the driving pin 941 and the key pin 942 aligns with the interface between the driving pin seat 92 and the key pin seat 93. Then the user rotates the key to rotate the driving pin seat 92 with the driving pins 941. The driving pin seat 92 is attached securely to other devices to unlock the tubular lock. When the incorrect key is inserted, each interface between the driving pin 941 and the key pin 942 misaligns with the interface between the driving pin seat 92 and the key pin seat 93 so that the driving pin seat 92 is blocked and is not rotatable relative to the key pin seat 93.
However, the conventional tubular lock has two shortcomings as follows.
First, the more positioning assemblies 94 the tubular lock has, the more permutation combinations of depths the recesses of the key can make. It also takes the thief more time to unlock the conventional tubular lock. However, the amounts of holes and the recesses of the pin seats 92, 93 are limited by the volume of the pin seats 92, 93.
Second, no matter how many positioning assemblies 94 the tubular lock has, all the positioning assemblies 94 are mounted axially. The thief only has to operate in the same direction to unlock the conventional tubular lock.
To overcome the shortcomings, the present invention provides a tubular lock and a key for the same to mitigate or obviate the aforementioned problems.